Prostaglandins E, E plus A plus B, F alpha, 15-keto-PGE, 15-keto-PGF alpha, 13,14-dihydro-15-keto-E, 13,14-dihydro-15-keto-PGF alpha, and 13,14-dihydro-PGF alpha will be measured in normal and malignant tissues and in culture fluids after maintenance of these tissues in organ culture. The following enzymes involved in the biosynthesis and metabolism of the prostaglandins will also be measured in these tissues before and during maintenance in tissue culture: 1) 15-hydroxy-prostaglandin dehydrogenase (types I and II), 2) delta 13,14 reductase, 3) prostaglandin interconvertase (PGE yields reversibly PGF), and 4) prostaglandin synthetase. All of these prostaglandins and their metabolites as well as the enzymes will be measured with the use of specific antibodies directed toward the product, the substrate or both. BIBLIOGRAPHIC REFERENCES: Armen H. Tashjian, Jr., Edward F. Voelkel, Janet McDonough, and Lawrence Levine. Hydrocortisone Inhibits Prostaglandin Production by Mouse Fibrosarcoma Cells. Nature 258, 739-741 (1975). Fred Kantrowitz, Dwight R. Robinson, Mary B. McGuire, and Lawrence Levine. Corticosteroids Inhibit Prostaglandin Production by Rheumatoid Synovia. Nature 258, 737-739 (1975).